Manufacture of concrete building blocks



Oct. 6, 1942. F. J. STRAUB MANUFACTURE OF CONCRET E BUILDING BLOCKS Filed 001i. 7, 1941 2 Sheets-Sheet ['INYENTO 5 By W to ATTORNEY Oct. 6,1942. STRAUB 2,298,074

MANUFACTURE OF CONCRETE BUILDING BLOCKS I Filed Oct. '7, 1941 2 Sheets-Sheet 2 I l l 4 a; QI 1 g l m ,1 1 I .12% j l I 25 g l z5 Q A! Va Jr lN VENTORM ATTO NEY Patented Oct. 6, 1942 2,298,074 MANUFACTURE OF CONCRETE BUILDING BLOCKS Francis J. Straub, New Kensington, Pa. Application October 7, 1941, Serial No. 413,963

16 Claims.

My invention is an improvement in the manufacture of building blocks from any suitable plastic aggregate, as sand and gravel, cinders, or the like, combined with a binder as cement, and sufiicient water for mobility in formation, followed by drying and resulting hardening.

The invention is in an improved method of treatment and apparatus therefor.

One well known practice in common use for many years, is to compress the aggregate within a suitable mold by tamping or continued compression, for resulting density of the aggregate and load resistance. Such practice is now largely superseded by vibrating the mold in a manner common in foundry practice.

The present invention has in view a surfacing or trowelling treatment of the side or end surfaces, or both, of the block, in a so-called vibrating machine. Following the former practice my prior Patents Nos. 1,651,420, 1,682,359, 1,692,355, 1,987,721, 2,099,946, 2,111,701 and 2,256,361,.relate to various means and operations in connection with tamping or pressing machines, for surfacing the side or end faces of the block.

The present improvement relates to the method and means utilized particularly in connection with a vibrating forming mold or molds, for effecting such surface treatment.

In vibration operations the aggregate is caused to settle compactly within the mold interior by gravity, induced by rapid vibration of the mold. The consistency of the aggregate must be sufilciently loose to utilize such treatment in order to fill the cavity effectively, and especially around the usual cores. The aggregate must also be sufilciently stiff and coherent to result in the formation of a block which can be promptly removed, and handled quickly and set aside for drying. While the density of a vibrated block is considerably less than that of a tamped or pressed block, its load resisting strength, when thoroughly dried, is however amply sufficient.

Particularly when composed of cinders with a fairly large proportion of fines the mixture with water and cement, of a proper consistency, gives excellent results in the usually desired qualities, while the fines of the raw material are readily subject to surfacing treatment. Ordinarily, such treatment is effected by trowelling the face or faces of the block while still comparatively wet and within the mold.

While very good results have been secured by various forms of such applications, the construction of commercial vibrating molding machines has not heretofore been adaptable to such surfacing operations.

In my present invention I utilize the essential qualityand eifect of vibration itself for transmission of movement to the surfacing element. either with or without actual movement-imparting means mounted on and with the vibrating mold member or members. In connection with the vibrated body of plastic aggregate the smoothing or trowelling treatment is accelerated; the finer particles of the main raw material are caused to concentrate on the surface of the block; and the actual settling of the main components within the mold interior and to all the corners and interstices thereof is effectually assisted.

Certain preferred constructions of a machine adapted to such operation are illustrated in the accompanying drawings in which:

Fig. l is a longitudinal vertical section through a machine provided with trowelling side walls, on the line I-I of Fig. 2;

Fig. 2 is a plan view of Fig. 1;

Fig. 315 a cross section on the line III-III of Fig. 2;

Fig. 4 is a sectional view similar to Fig. 1 illustrating vertical reciprocation of the end walls of a mold;

Fig. 5 is a partial plan view means for vertical movement of both side and end walls;

Fig. 6 is an enlarged interior detail view showing the actuating eccentric mechanism in receded position;

Fig. 7 is a similar view showing the same in its opposite inward position;

Fig. 8 is a cross sectional view on the line VIIIVIII of Fig. '7;

Fig. 9 is a sectional detail view showing one form of spring resisting and supporting means of Fig. 4 showing walls 0' for the reciprocating side walls;

Fig. 10 is a similar view showing a modified construction.

In vibrating mold apparatus .the main mold member 2 is loosely mounted upon suitable foundations 3 for upward and downward vibration by any suitable actuating means, as cams 4, or otherwise.

Such molding constructions are generally well understood and need not be further described. However, because of their mobility, it is advisable to combine any actuating mechanism directly with the vibrating mold itself, whatever its degree of movement is. Ordinarily, and as in the present case, the movements of the mold and of the trowelling plate or plates are comparatively limited to small fractions of an inch, and at relatively high speed.

In the construction illustrated herein, when the side faces of the block are to be treated, I utilize one or a pair of side plates 5, of the main mold member 2, as in Figs. 1 and 2. The side plates 5 are connected by any suitable means, as cross heads 1, and are adapted to move longitudinally back and forth beyond the opposite edges of end walls 6, as the result of vibration itself, or as positively driven.

For such latter purpose I utilize an impeller 8 which, as shown, is in the form of an eccentric drive adapted to engage the end of a plunger 9 fastened to one of the cross heads 1 for actuating it and the side plate or plates 5 inwardly at each rotation of the eccentric. Reverse movement is effected by spring units I and II, at opposite ends, as shown in Fig. 2, by which the side plates are cushioned and maintained in all positions by such oppositely acting spring units. It will be observed that the strength of the opposite spring members and their pressure may be regulated by varying the relative springs, or by adjusting screws I 2, so that the side plates will promptly return after each thrusting movement by the eccentric 8, and will at all times be firmly held and balanced between the spring units, without other support.

Because of the balancing efiect of the oppositely arranged springs Ill and H the plates are maintained throughout all operations in a floating condition, without other support, under correcting action of the oppositely acting springs.

In this respect the device is extremely effective and essentially different from any other smoothing element or elements heretofore utilized within my experience.

The thrusting assembly 8, in the form shown as an eccentric drive, is mounted upon and movable with the main mold itself, as by supporting bearing arms l3 for main shaft l4 and its eccentric I do, the shaft being provided with a pulley or other drive I 5 from any suitable prime mover.

As shown in Figs. 2 and 3 I may provide additional side bearing spring units l6 which may be utilized in connection with extra long side plates, or omitted when not necessary.

Either with or without such side springs however, one or a pair of trowelling plates 5 will be continuously maintained between the opposite spring units In and H during their back and forth movements and are in effect floating trowelling members. When but a single trowelling plate is used, it will be understood that ac tion of the impeller 8 should be directly edgewise of such plate, against opposing spring action.

The binding action of the springs and their lateral resiliency tend to maintain the pair of plates always in suspended position, either in their normal position as shown, or slightly tilted in one direction or another, or slightly higher or lower than a middle position. but always tending to resume and maintain an approx mately middle position during their frequent rapid back and forth movements.

When the side spring units l6 are utilized they tend to maintain close relationship between the side plates 5 and end plates 6. Under the comparatively short thrust and return movements of the side plates, the springs are quite sufliciently resilient laterally to accommodate themselves to all such rapidly changing, very comparatively short alternations.

The eccentric drive member 8, shown in detail in Figs. 6, 7 and 8, is designed to impart rapi comparatively short movements through tl plunger 9 by its surrounding rim ll, betwee which and the eccentric I 8 is a series of roll bearings, as balls I9. Shaft I4 is in driving cor nection with the eccentric by any suitable meal as key 20, and as thus constructed, depending the R. P. M. of shaft I4, plunger 9 will be thru inwardly merely by pressure of rim I! at eac rotation of the eccentric within the relative stationary rim.

Other means for delivering relatively short ar extremely rapid vibrations or oscillations to tl plates may be utilized within the purposes of ti invention.

It will be understood also that instead of hor zontal oscillation or trowelling the machine ma be provided with vertically movable end plates 6 and cooperating vertically movable side plates 51 as in Figs. 4 and 5. In such case the eccentr: impellers 8 are located at each end and each sic of the machine, and suitably connected with ac tuating gearing not necessarily herein shown, fc the purpose of impelling said end and/or sid plates upwardly, and by spring action down wardly, throughout the entire moving operatic! For the same object and purpose in maintain ing one or both end plates and side plates in normally suspended or floating condition, I uti lize similar spring units Ilia as shown in Fig.

These as shown are mounted around a support ing stem 2| slidably held by a bearing 22 fro: the main end wall of the machine as shown. Th side walls 5a and end walls So have similar sprin resisting brackets 23 and cooperating spring cup 24a, secured to and movable with stem 2|, 5 that at each impulse of the eccentric impeller and plunger 9a, the walls 5a and/or So will b thrust upwardly with reverse compensating sprin action, for each alternation of the eccentric.

The several eccentrics, or other suitable actu ating means, may be arranged suitably dependen on the size, capacity, design, or other condition of the molding machine itself.

It will be understood that the spring units ma; be of the construction shown in the principal fig ures and in- Fig. 9, or with reversed cups 24 i1 connection with the adjusting screws 12, for ac curately tempering the spring pressure whereve desired.

In respect of such control it is desirable t1 maintain a somewhat greater reacting sprin pressure through units In opposite the positivl impelling action of the eccentric, whereby t4 promptly return the side plates against the les, active or relatively Weaker pressure of Sprint units ll, all such conditions being easily regu lated as to pressure, within the conditions am limitations of the particular machine and it; operation. If desired, rubber or any other resil ient means, may be substituted for the springs It will be understood of course that the ma chine is operated in connection with the usua supporting pallet 25 and bottom plate 26 to: support and ejection of the molded block afte: completion of the operation, as by plungers 2'. or other suitable means of conventional form In the case of a cored block the cores 28 ma be utilized, as indicated in dotted lines in Fig. l

The construction and operation of the machinl will be readily understood from the foregoing description. It results in the making of a building block, especially where coarse, intermediate and fine cinders are utilized, which will be perfectly formed as to itsrectangular shape anc dimensions, and which will have at the same time a smooth trowelled surface when treated as above described.

In connection with the rapid vibrations of the machine and its contents during filling, together with the equally rapid oscillations of the smooth ing plate or plates, the side and/or end surface portions will become congested with the finer particles, resulting in practically smooth, even faces throughout.

A further advantage is that the face treatment of the block as described also tends to materially assist the settling of the aggregate into all parts of the mold evenly and thoroughly.

Furthermore, the consistency of the finished block, when made on a vibrating machine, and its comparatively slight density provides for a very satisfactory cellular structure and penetrability as by nails, while maintaining its load bearing strength when thoroughly dried, without irnpairment.

What I claim is:

1. The method of making a building block con sisting in filling a vibrating forming mold with plastic concrete and simultaneously smoothing a face of the block by alternating movement of a resiliently suspended floating facing member operating independently of vibration.

2. The method of making a building block consisting in filling a vibrating forming mold with plastic concrete and simultaneously smoothing a face of the block by alternating movement of a resiliently suspended facing member in varying uncontrolled directions and independent of vibration.

3. The method of making a building block consisting in filling a vibrating forming mold with plastic concrete during vibration of the mold and simultaneously smoothing a face of the block by alternating rubbing action thereagainst independent of vibration and in variably different directions.

4 The method of making a building block consisting in molding and vibrating plastic concrete while imparting to a molded surface of the block in formation and during its vibration, a smoothing treatment by rubbing action against the block independent of its vibration and in variably diiferent directions.

5. A block molding machine consisting of an aggregate containing casing provided with a loosely mounted floating trowelling plate, cushioning springs at opposite ends thereof, and a one way impeller for the plate.

6. A block molding machine of the vibrating type consisting of an aggregate containing casing provided with a loosely mounted floating trowelling plate, cushioning springs at opposite ends thereof, and a one way impeller for the plate.

7. A block molding machine consisting of an aggregate containing casing provided with a loosely mounted floating trowelling plate having longitudinal and lateral freedom of movement supported between oppositely acting cushioning springs, and an impeller for the plate.

8. A block molding machine of the vibrating type consisting of an aggregate containing casing having a relatively movable confining and smoothing wall, endmost cushioning springs tending to support the wall between them for reciprocating movement, springs exerting pressure inwardly of the middle portion of said movable wall, and

means on the vibrating molding machine for imparting reciprocating movement to said wall.

9. In combination with a main molding machine consisting of an aggregate containing casing having fixed end walls, oscillating side enclosing and smoothing plates, endmost oppositely acting cushioning springs therefor, and means for actuating the side plates towards one of said springs.

10. In combination with a main molding machine consisting of an aggregate containing casing having fixed end walls, oscillating side enclosing and smoothing plates, cushioning springs at each opposite end thereof, and means for positively moving the side plates in one direction towards the reacting springs at the opposite end of the side plates.

11. In combination with a main molding machine consisting of an aggregate containing casing having fixed end walls, an oscillating side enclosing and smoothing plate, endmost cushioning springs therefor, and means for actuating the side plate toward the outermost opposing spring for return movement thereby.

12. In combination with a main molding machine consisting of an aggregate containing casing having stationary end walls, an oscillating enclosing and smoothing side plate, endmost cushioning springs H therefor, a plunger adapted to thrust the side plate towards an endmost opposing spring, and an actuating plunger having an impelling eccentric or the like engageable therewith.

13. In combination with a main molding machine consisting of an aggregate containing casing having stationary end walls, an oscillating enclosing and smoothing side plate, endmost cushioning springs therefor, pressure varying adjusting means for said springs, a plunger adapted to thrust the side plate towards an endmost 0D- posing spring, and an actuatingplunger having an impelling eccentric or the like engageable therewith.

14. In combination with a main molding machine consisting of an aggregate containing casing having a vertically movable wall endmost, supporting and balancing springs for said wall tending. to maintain it in suspended balanced position and means for intermittently elevating said wall against spring pressure for oscillating facing smoothing of the confronting face of the molded block in formation.

15. In combination with a main molding machine consisting of an aggregate containing casing having a vertically movable wall, supporting and balancing springs for said wall tending to maintain it in suspended balanced position, guiding stems for the springs, upper and lower springengaging brackets on the wall, a spring-compressing thrusting plunger for the lowermost bracket, and an intermittently operating impeller for said plunger.

16. The method of making a building block consisting in molding and vibrating plastic concrete within an enclosing mold while imparting to a molded surface of the block in formation and during its vibration a smoothing treatment by alternating back and forth rubbing action against the block in combination with unlimited cooperating rubbing action in variably different directions.

FRANCIS J. STRAUB.

CERTIFICATE OF CORRECTION. Patent No. 2, 298,07h. October 6, l9lt2.

FRANCIS J STRAUB It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, second column, line 14,6, claim 11;, for "wall endmost, read "wall, endmost-; and that the said Letters Patent should be read with this correction therein that the same may conform to the record. of the case in the Patent Office.

Signed and sealed this 1st day of December, A. D. 1911.2.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

